JPH086262A - Method for hardening film of water-soluble photoresist - Google Patents

Abstract

PURPOSE:To provide a method for hardening a film which is capable of forming a resist film having good etching resistance and good adhesiveness to a thin metallic sheet without generating chipping of the resist film in spite of prolonging of etching time, does not degrade the resolution of the resist film, does not degrade productivity and does not require a large burning furnace. CONSTITUTION:The thin metallic film 30 subjected to development processing in a development processing section 12 is immersed into a hardening liquid 38 and is washed with water in a washing section 16. After the thin metallic sheet is subjected to draining in a draining section 18, the sheet is subjected to a first heat treatment in the state of stretching the thin metallic sheet in a first burning treatment section 20 and the thin metallic sheet subjected to this heat treatment is taken up in the form of a coil 54 and is subjected to a second heat treatment in the form of the coil in a second burning treatment section 24.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a water-soluble photo resist after development processing applied to the surface of a long thin metal plate in a series of steps for manufacturing a shadow mask for a color CRT by a photo-etching method. The present invention relates to a hardening method for hardening a resist (hereinafter, simply referred to as "resist").

[0002]

2. Description of the Related Art A series of steps in a photoetching method will be described by taking a case of manufacturing a shadow mask as an example.

The shadow mask is generally manufactured in large quantities and continuously, and the shadow mask material is sent from the steel plate manufacturer to the shadow mask manufacturer in the form of a coil having a weight of 1 to 2 tons. In general, the shadow mask material fed from the coil is subjected to various treatments in a long strip shape, and after the series of steps of photoetching is finished, the long strip is cut into a single-wafer form.

First, it has a long strip shape and a plate thickness of 0.05 to
Degrease the shadow mask material such as 0.3 mm low carbon aluminum killed steel or Invar type alloy containing 36% nickel, remove the rust preventive oil on the surface, wash with water, and then use an acidic solution or alkaline solution to prepare. Surface treatment and washing with water (surface preparation step). Next, resist on both sides of the shadow mask material,
For example, a resist made by adding a dichromate or an azide compound as a sensitizer is applied to a base material made of casein or PVA (polyvinyl alcohol), dried, and the front and back surfaces of the shadow mask each have a thickness of several μm.
The resist film is deposited and formed (coating step). Next, on the surface of each resist film deposited on both front and back surfaces of the shadow mask material, each master pattern having a required image corresponding to the electron beam passage hole to be formed,
Exposure is performed by aligning the image positions on the front and back so that they are in close contact with each other (baking process). Subsequently, the resist film is developed using warm water or the like to form a resist film having a desired pattern image on both main surfaces of the shadow mask material (developing step). After immersing the shadow mask material in a hardening solution, for example, chromic anhydride solution, the resist film is dried and strengthened by performing a burning process (heating process) with hot air or an infrared heater at a temperature of 150 to 280 ° C. Do (hardening step). After spraying both main surfaces of the shadow mask material with a ferric chloride aqueous solution to form a large number of through holes, the resist film is peeled off from both surfaces of the shadow mask material (etching step). Finally, the shadow mask material is cut into pieces one by one to obtain a sheet-shaped shadow mask (shearing step).

In the above series of photo-etching steps, the burning treatment after the shadow mask material is immersed in the hardening liquid after the developing treatment is performed by hardening the unreacted casein or PVA to form the resist film at the time of etching. This is because the casein and PVA are hardened by heat in this hardening treatment.
It is utilized that trivalent chromium becomes trivalent chromium and crosslinks with casein or PVA.

As a method of hardening treatment, for example, Japanese Patent Laid-Open No.
No. 7-148859, a chromic anhydride solution or a dichromate solution is applied to the surface of a resist film after development by dipping or spraying, followed by washing with water, substituting water with alcohol, and drying, followed by burning treatment. A method of applying is disclosed. Further, Japanese Patent Publication No. 3-62264 discloses that after exposing the exposed resist with water and developing it,
Drain with a squeezing roller or air knife, and then immerse the resist in an aqueous solution of chromic acid anhydride, and spray the aqueous solution of chromic acid anhydride on the resist by a spray method or a shower method before and after this immersion, and then wash and wash the resist. After that, a method is disclosed in which water is removed by a squeeze roll, water is further removed by a hot air type air knife, and then the resist is burned. With these methods,
The hexavalent chromium of chromic anhydride or dichromate is reduced to trivalent chromium by burning, and the reduced 3
By the cross-linking reaction due to the bond between valent chromium and casein,
I try to harden the resist.

[0007]

By the way, in recent years, color CRTs are required to have a large screen, high brightness and high definition. The shadow mask used in such a color CRT tends to have a large thickness in order to prevent image shake due to thermal expansion and vibration during use of the CRT. The thicker the shadow mask, the longer the time required to etch the shadow mask material when manufacturing the shadow mask. Here, a resist composed of casein and dichromate is generally used in the production of the shadow mask. However, when the etching time of the shadow mask material is long, the resist is used to adhere to the surface of the shadow mask material. There is a problem that the formed resist film cannot withstand etching for a long time. That is, as shown in a partially enlarged cross-sectional view in FIG. 2, during etching of the shadow mask material 1 having a resist film 2 of a desired pattern image deposited on the surface, a part of the resist film 2 has a chip 3. That is, if the etching is continued as it is, the shadow mask material 1 in the portion where the chip 3 is generated is excessively etched to form a hole 4 larger than a normal hole, which causes a defect of the shadow mask. There's a problem.

It is considered that the cause of chipping in the resist film is that thermal denaturation of casein during burning causes the resist to become too hard and carbonized, so that the resist film becomes rather brittle. Therefore, as a countermeasure against this, it is considered to lower the burning temperature to prevent thermal denaturation of casein,
This actually reduces the occurrence of chipping of the resist film. However, when the burning temperature is lowered, chromium in the dichromate is not completely reduced from hexavalent to trivalent during burning, and the crosslinking between chromium and casein becomes insufficient. As a result, the resist film is dissolved in the etching solution during etching, or the adhesion between the resist film and the shadow mask material is deteriorated, and the through holes formed in the shadow mask material by etching become large.
A new problem will arise.

In this case, even if the burning temperature is lowered, it is possible to completely reduce hexavalent chromium to trivalent chromium by prolonging the burning time. However,
For example, in the case of performing burning with hot air, burning at a temperature of 240 ° C. for 2 minutes can reduce trivalent chromium, whereas burning at a temperature of 200 ° C. that does not cause chipping of the resist film during etching can be performed. If this is done, the processing will take more than 10 minutes. Then, in order to lengthen the burning time, if the conveying speed of the shadow mask material in the shadow mask manufacturing line is lowered, the time for developing the resist film using hot water or the like becomes too long and the resolution of the resist film deteriorates. As a result, productivity will drop significantly. On the other hand, the method of lengthening the burning time by lengthening the burning furnace without lowering the conveying speed of the shadow mask material has a problem that a very large burning furnace is required. As described above, the method of lowering the burning temperature and lengthening the burning time has not been practically applicable in the past.

The present invention has been made in view of the above circumstances, and even when the etching time is long, the resist film is not chipped at the time of etching, and the etching resistance and the metal resistance are improved. It is possible to form a resist film with good adhesion to a thin plate, without reducing the resolution of the resist film or reducing productivity, and without requiring a very large burning furnace. An object of the present invention is to provide a method for hardening a water-soluble photoresist.

[0011]

According to the present invention, when a hardening liquid is supplied to a long strip-shaped metal thin plate and then the metal thin plate is heat-treated, the metal thin plate is heated in a stretched state. The first heat treatment step of applying the heat treatment, the winding step of winding the elongated metal thin plate subjected to the heat treatment into a coil, and the heating of the metal thin plate in a coiled state. The second heat treatment step of performing the treatment is performed.

[0012]

When the resist is hardened by the above-described method, in the first heat treatment step, the temperature is set so that the resist does not become too hard or carbonized, for example, 200.
The metal sheet is heat treated at a temperature of ° C for a conventional time, for example 2 minutes. Since this heat treatment is carried out at a lowered treatment temperature for a conventional treatment time, the hexavalent chromium of dichromate or chromic anhydride is not completely reduced to trivalent chromium by this heat treatment. Although the chromium in the part remains in the hexavalent state, the thin metal plate in the stretched state is once wound into a coil. Then, in the second heat treatment step, the heat treatment is collectively performed over the entire length of the coiled metal thin plate. Also in this step, the heat treatment of the thin metal plate is performed at a temperature at which the resist does not become too hard or carbonization occurs, for example, at a temperature of 180 ° C., but the treatment is performed for a relatively long time, for example, 30 minutes to 5 hours. Be done.

As described above, in the film-hardening method according to the present invention, the heat treatment can be carried out at a relatively low temperature, so that the resist film becomes too hard or carbonized to make the resist film brittle. There is no. On the other hand, in the second heat treatment step, the metal thin plate can be heat-treated for a treatment time sufficient to completely convert the chromium into trivalent, so that the etching resistance of the resist film and the resist film and the metal thin plate can be improved. The adhesiveness with can be improved.
The heat treatment in the first heat treatment step may be performed within a range in which the transport speed of the metal thin plate in the shadow mask manufacturing line is not reduced, so that the development processing time becomes too long or the productivity is reduced. Also, the heat treatment in the first heat treatment step may be performed using a conventional burning furnace. Further, in the second heat treatment step, since a plurality of coils can be collectively heat treated for the metal thin plate wound in a coil shape, a series of processing treatments can be performed without lowering productivity. .

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described below with reference to FIG.
Will be described with reference to.

FIG. 1 is a schematic view showing an example of an apparatus configuration for carrying out a film-hardening method according to the present invention, schematically showing the configuration of a developing / hardening processing unit in a shadow mask manufacturing apparatus. Is. This device comprises a long strip metal thin plate (shadow mask material) supply unit 10, a development processing unit 12, and a film hardening liquid supply unit.
14, water washing section 16, draining section 18, first burning processing section 20
And a thin metal sheet winding section 22 and a second burning processing section 24. Then, both places of the first burning processing unit 20 and the second burning processing unit 24 are
It is communicated by the coil carrier 26.

The metal thin plate supplying section 10 holds a metal thin plate having a baked resist film deposited on its surface in the form of a coil 28, and the metal thin plate 30 is continuously fed from the coil 28. It has become. Sheet metal feeder 10
The thin metal plate 30 fed out from is conveyed to the development processing unit 12. The development processing section 12 is provided with a developing tank 32,
The thin metal plate 30 is introduced into the developing tank 32,
While the sheet 30 passes through the developing tank 32, a plurality of spray nozzles 34 are arranged in rows on both sides of the sheet transporting path of the metal sheet 30, and hot water such as 4
The hot water of 0 ° C. is sprayed and the development processing is performed. The developed thin metal plate 30 is conveyed to the hardener supply unit 14. The hardening fluid supply unit 14 includes a hardening solution, for example, an aqueous solution of chromic anhydride.
A hardening fluid tank 36 accommodating 38 is arranged, and the thin metal plate 30 is immersed in the chromic anhydride aqueous solution 38 in the hardening fluid tank 36. Further, a pair of shower nozzles 40 are arranged on both sides of the metal thin plate 30 above the hardening liquid tank 36, and the metal thin plate is placed in the chromic anhydride aqueous solution 38 in the hardening liquid tank 36. Prior to the immersion, a chromic anhydride solution is sprayed from the pair of shower nozzles 40 onto both main surfaces of the thin metal plate 30. As the means for supplying the hardening liquid to the thin metal plate, the dipping method and the coating method applied from the shower nozzle are used together in the illustrated example, but the hardening liquid is applied only by one of the methods. It may be supplied to a thin plate, or a spray system may be adopted.

A thin metal plate 30 having a hardener supplied to both principal surfaces.
Are transported to the water washing section 16. The washing section 16 is provided with a washing tank 42. Inside the washing tank 42, a plurality of spray nozzles 44 are provided on both sides of the metal thin plate 30 along the conveyance path.
Are lined up. Then, the thin metal plate 30 is washed by being sprayed with hot water, for example, 40 ° C. hot water, from the plurality of spray nozzles 44 to both main surfaces while passing through the washing tank 42. A pair of squeezing rollers 46 are arranged at the outlet of the washing tank 42, and a pair of air knives 48 are arranged in parallel on the rear side of the squeezing rollers 46 in the conveying direction. When the thin metal plate 30 passes through the draining section 18 in which the squeezing roller 46 and the air knife 48 are arranged, the thin metal plate 30 after being washed is drained. As a means for draining water, a method of squeezing the surface of the metal thin plate with a film or a rubber plate may be adopted.

The drained metal sheet 30 is conveyed to the first burning processing section 20. First burning processing unit 20
In the burning chamber 50, a plurality of infrared heaters 52 are arranged in rows inside the burning chamber 50 along the transport path of the thin metal plate 30, respectively. Then, a thin metal plate is placed inside the burning chamber 50.
During the passage of 30, the thin metal plate 30 has a temperature such that the resist does not become too hard or carbonized, for example, 200 ° C.
Heated to a degree. In the first burning unit 20, heat treatment may be performed to such an extent that the resists do not adhere to each other when the thin metal plate 30 is wound into a coil shape as described below. It passes through the burning chamber 50 to some extent. still,
Hot air may be used to heat the thin metal plate, or an induction heating method or the like may be used.

The thin metal plate 30 which has been subjected to the first heat treatment in the first burning treatment section 20 is temporarily wound in the form of the coil 54 in the winding section 22 of the thin metal plate through the driving roller 56. . Reference numeral 58 in the figure denotes a roller for transporting a thin metal plate.

The coil 54 made of a thin metal plate is transferred to the coil carrier 26 and is carried to the second burning processing section 24 by the coil carrier 26. In the second burning processing section 24,
A heat treatment chamber 60 is provided, and a plurality of coils 54 can be accommodated in the heat treatment chamber 60 at the same time. Heat treatment room
60 includes a steam generating boiler 64, a heat exchanger 66 and a fan 68.
A hot air supply device 62 provided with is installed side by side, and by supplying hot air into the heat treatment chamber 60 by the hot air supply device 62, the ambient temperature in the heat treatment chamber 60 can be maintained at, for example, 180 ° C. Has become. Then, a plurality of coils 54 are accommodated in the heat treatment chamber 60 at the same time, the inside of the heat treatment chamber 60 is maintained at a temperature of 180 ° C., and a second heating is performed on the thin metal plate in the form of the coils 54, for example, for 30 minutes to 5 hours. The treatment is performed, and the dura treatment is completed.

Using the apparatus having the above-mentioned structure, the thin metal plate 30 having the resist film after baking deposited on both main surfaces is used.
In a stretched state while being sequentially conveyed to the development processing section 12, the film hardening solution supply section 14, the water washing section 16, the water draining section 18 and the first burning processing section 20, the metal thin plate in the form of the coil 54 is first processed. The resist film deposited on both main surfaces of the metal thin plate 30 is developed and hardened by being conveyed to the burning processing unit 24 of No. 2 and processed, and a resist film having a required pattern image is formed on both main surfaces. A thin metal plate that is adhered and formed is obtained. Then, in this film hardening method, the burning treatment is divided into two steps and is performed at a relatively low temperature of 200 to 180 ° C., and the second heating treatment in the second burning treatment section 24 is performed completely. In addition, the metal thin plate is heat-treated for a sufficient treatment time so that chromium becomes trivalent. Therefore, the resist film does not become brittle because the resist becomes too hard or carbonized, and a resist film having excellent etching resistance and adhesion to a thin metal plate can be obtained. Then, the series of steps from the developing process to the first heat treatment is performed on the metal thin plate 30.
Since it suffices to keep the transport speed of
The development processing time does not become too long, and the processing can be performed using the conventional equipment as it is. Further, in the second burning processing unit 24, since the plurality of coils 54 are collectively heat-treated for the thin metal plate, it is possible to perform the treatment without lowering the productivity.

As the resist, milk casein or P
In addition to VA, natural polymers such as fish glue, gelatin and egg white, or synthetic polymers such as polyacrylamide added with dichromate, diazonium salt and azide compound as sensitizers are generally used. However, for the purpose of improving the etching resistance of these resists and the adhesion to the substrate, after the development treatment, a hardening treatment is performed using a solution of dichromate, diazonium salt, azide compound, aldehyde, etc. You may do it. These cases are also the same in that the thermosetting of the polymer compound and the crosslinking reaction by the hardener are used, and the present invention can be applied in the same manner.

[0023]

Since the present invention is constructed and operates as described above, when the film hardening process of the resist is carried out by the film hardening method according to the present invention, even if the etching time becomes long, the etching is performed. Sometimes, the resist film is not chipped, and it is possible to form a resist film having good etching resistance and adhesion to a thin metal plate, and the development processing time is the same as that of the conventional resist film. Therefore, the resolution does not decrease, and therefore, a good shadow mask in which proper through holes are formed can be obtained. In addition, it is possible to maintain high productivity, and without requiring a very large burning furnace,
The conventional equipment can be used as it is by simply adding heat treatment equipment for carrying out the second heat treatment step. Since the second heat treatment is performed in a state where the thin metal plate is wound into a coil, the heat treatment equipment to be added can be made compact.

[Brief description of drawings]

FIG. 1 shows an example of an apparatus configuration for carrying out a water-soluble photoresist film-hardening method according to the present invention, and schematically shows the configuration of a developing / hardening processing unit in a shadow mask manufacturing apparatus. It is a schematic diagram.

FIG. 2 is a diagram for explaining a problem in a conventional film-hardening method and is a partially enlarged cross-sectional view of a shadow mask material.

[Explanation of symbols]

 12 Development Processing Section 14 Hardening Liquid Supply Section 16 Water Washing Section 18 Draining Section 20 First Burning Processing Section 22 Metal Thin Plate Winding Section 24 Second Burning Processing Section 30 Elongated Metal Thin Plate 32 Developing Tank 34 Spray Nozzle 36 Hardening liquid tank 38 Hardening liquid (chromic anhydride solution) 40 Shower nozzle 42 Washing tank 44 Spray nozzle 46 Squeeze roller 48 Air knife 50 Burning chamber 52 Infrared heater 54 Coil with thin metal plate 60 Heat treatment chamber 62 Hot air supply apparatus

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yushi Hamada 1 Horikawa-dori Teranouchi, Kamigyo-ku, Kyoto 1 Tenjin Kitamachi 1-chome, Dai Nippon Screen Manufacturing Co., Ltd.

Claims (1)

[Claims] 1. A hardening film of a water-soluble photoresist, comprising supplying a hardening solution to a long strip of metal thin plate having a water-soluble photoresist film whose surface has been subjected to development treatment, and then heat-treating the thin metal plate. In the method, a heat treatment of a thin metal plate is performed by a first heat treatment step in which the thin metal plate is stretched, and a stretched state in which the heat treatment is performed in the first heat treatment step. And a second heat treatment step of subjecting the metal thin plate to a heat treatment on the metal thin plate in a coiled state. Hardening method for water-soluble photoresist.